(a) Field of the Invention
This invention relates to a liquid piston heat engine or heat pump using a Stirling cycle engine design and having a multiple cylinder array which is capable of producing rotary motion.
(b) Discussion of Prior Art
In 1816 a Scottish clergyman by the name of Robert Stirling invented a heat engine for a source of mechanical power wherein a gas-filled cylinder is alternately heated and cooled for moving a piston back and forth from one end of the cylinder to the other end of the cylinder. The Stirling engine competed with the steam engine, before both were displaced by the internal combustion engine at the start of the twentieth century. Today a great deal of research is being conducted using the Stirling engine cycle design, not as an engine, but for example as a refrigeration heat pump for refrigerators. Helium, a gas which is inert and nontoxic, is being used in the current Stirling pump research. If the new Stirling engine refrigeration designs are successful the use of ozone depleting chlorofluorocarbons (CFC's) would be eliminated. CFC's used as a refrigerant were introduced in 1931 by DuPont Co. under the trademark Freon. CFC's and substitutes thereof are expensive and are believed to be harmful to our environment.
In the early 1970's Colin D. West, a leading authority on Stirling engine technology, disclosed a Stirling cycle liquid piston engine activated by a heated and cooled gas which could be used as a simple, low cost, heat pump. This Stirling cycle liquid piston design is known as the "Siemens" arrangement. By using a multi-cylinder configuration of this arrangement, which is referred to as a "fluidyne", a system can be designed in which all liquid columns are subject to both gas-pressure as well as gravity. West's work related to Stirling cycle heat engines is well documented in numerous published articles as well as in British Patents 1,487,332; 1,507,678; 1,329,567; 1,568,057; 1,581,748; and 1,581,749.
In Erazo U.S. Pat. No. 4,130,993 and Baer U.S. Pat. No. 4,134,264 variations of the Siemens arrangement using a Stirling heat engine or heat pump are described wherein an oscillating liquid motion in a plurality of cylinders produces rotational motion. The Erazo and Baer engines, when rotated on an axis beyond the centrifugal velocity of the oscillating liquid, and with heating and cooling supplied to the system, the rotary motion of the engines on the axis is sustained. Both of these engines rotate about a concentric axis which is used for rotary power, which is useful for example for generating electricity and the like.
The above mentioned adaptations of the Stirling cycle all have a shortcoming in that their designs provide only a limited surface area on the cylinders which inherently limits heat transfer capability. Also and more importantly none of these known earlier engine designs provide the advantage of using multiple cylinder arrays which are offset from a rotating axis for increased moment force in sustaining rotatable velocity of the system.
None of the above mentioned patents describe or disclose teachings of a unique heat engine or heat pump for producing rotary motion incorporating a Stirling cycle with liquid piston as described herein.